On Surface Properties of Molten Aluminum Alloys of Oxidized Surface

The nature and the role of the oxide layer covering the Al alloys is considered on the base of review of literature and some models. It has been found that the oxygen on the surface of the molten Al is in a state of a supercooled Al sub 2 O sub 3 , which has an associated structure. The Gibbs' equation was modified to calculate the surface tension of molten Al alloys of oxidized surface. Components, which have higher chemical activity to O than Al are more surface active in alloys of oxidized surface than in alloys of unoxidized surface, and vice versa. The model has been developed to calculate contact angle between Al of oxidized surface and different refractories. The common temperature dependence of contact angle in systems of molten-Al /solid-refractory is given. The role and mechanism of different parameters (temperature, total pressure, alloying element, nature of refractory) are discussed. The contact angle between molten Al and the oxide layer covering the melt has been estimated.